PHP - Insert Dynamic Number Of Checked Box Values To Database

<?php
require('dbconnection.php');



$a=$_POST['a'];
$b=$_POST['b'];

class cal{

 
public function insert($a,$b){

if((($a)&&($b))!="")
{
 $c=$a*$b;

$sql = "INSERT INTO cropplant (sbetweenQ ,sbetweenC ,sbetweenTC ) VALUES ('$a', '$b', '$c')";
$query = mysql_query($sql);
if(!$query)
		{
			echo '<script type="text/javascript">alert("DB Update error ! please Re-enter your details.");</script>'; 
		

		}else
			{
			echo '<script type="text/javascript">alert("New Cropplant Added Successfuly.");</script>'; 
			
		}


}else{

echo"please enter all";
}
}
}


?>

Dear All Members

here is my table data..

(4 Columns/1row in mysql table)

id                 order_no               order_date                  miles
310                001                   02-15-2020                MI,108.53
                                                                                     Oh,194.57
                                                                                     PA,182.22
                                                                                     WA,238.57

How to split(miles) single column into (state, miles) two columns and output like following 5 columns /4rows in mysql using php code.

(5 Columns in mysql table)
------------------------------------------------------------------------------------

id                  order_no              order_date              state      miles

310                001                   02-15-2020               MI          108.53

310                001                   02-15-2020              Oh          194.57

310                001                   02-15-2020              PA          182.22

310                001                   02-15-2020             WA          238.57
 

------------------my php code -----------

<?php
//invoice.php  
include('../includes/config.php');

if(isset($_POST["add"]))
{
$order_no=$_GET['order_no'];
$order_date=$_GET['order_date'];
$miles=$_POST['miles'];

$miles = explode("\r\n", $_POST["miles"]);
$newdata = "'" . implode("','", $_POST["miles"]) . "'";
$sql ="INSERT INTO tble_states_miles(order_no,order_date, miles) VALUES(:order_no, :order_date, :newdata)";

$query = $dbh->prepare($sql);
$query-> bindParam(':order_no', $order_no, PDO::PARAM_STR);
$query-> bindParam(':order_date', $order_date, PDO::PARAM_STR);
$query-> bindParam(':miles', $newdata, PDO::PARAM_STR);

$lastInsertId = $dbh->lastInsertId();
if($lastInsertId)
{
echo "<script type='text/javascript'>alert('Added Sucessfull!');</script>";
echo "<script type='text/javascript'> document.location = 'ifta_miles_calculationlist_added.php'; </script>";
}
else 
{
$error="Something went wrong. Please try again";
}

if($query->execute()) {

$sql = "update tis_invoice set flag='1' where order_no=:order_no";
$query = $dbh->prepare($sql);
$query-> bindParam(':order_no', $order_no, PDO::PARAM_STR);

$query->execute();

}
}
?>

----------------- my form code ------------------

 <?php
                   $order_no=$_GET['order_no'];
        $sql = "SELECT * from tis_invoice where order_no = :order_no";
        $query = $dbh -> prepare($sql);
        $query->execute(
  array(
   ':order_no'       =>  $_GET["order_no"]
  )
 );
        $result = $query->fetchAll();
        foreach($result as $row)
?>
    
                    <form method="post">
                        <table align="center" style="width: 55%">
                        <tr><td>Invoice Number</td></tr>
                        <tr><td><input type="text" name="order_no" value="<?php echo $row["order_no"]; ?>" readonly=""></td></tr>
                        <tr><td>Invoice Date</td></tr>
                        <tr><td><input type="text" name="order_no" value="<?php echo $row["order_date"]; ?>" readonly=""></td></tr>
                        <tr><td>
                               <textarea name="miles" class="form-control" rows="10" placeholder="" required></textarea>
                           </td></tr>
                           <tr><td>
                         
                            <input type="submit" name="add" class="btn btn-primary" value="Add" />
                       </td></tr></table>
                    </form>

-- Can any one help how to correct my code..present nothing inserted on table

Thank You

<?php $s1 = mysql_query("SELECT pages.page_id, pages.code, pages.page, pages.href, access_level.aid, access_level.page_id as pgid, access_level.department, access_level.position, access_level.active FROM pages LEFT OUTER JOIN access_level ON pages.page_id=access_level.page_id WHERE access_level.department=".$department." AND access_level.position=".$position." AND pages.code='sn'") or die(mysql_error());
				while($s2 = mysql_fetch_array($s1)) { ?>
				<tr><td><li><?php echo $s2['page']; ?>  </td><td><input type="checkbox" name="sn[]" value="<?php echo $s2['page_id']; ?>"  
                <?php if($row['pgid'] === $s2['page_id']) echo 'checked="checked"';?> />

<?php
include("Database.php");

$db = new Database();
var_dump($db);

$table = "users";
$whitelist = array('username', 'password');
$data = array_intersect_key($_POST, array_flip($whitelist));

if(isset($_POST['username']) AND ($_POST['password']))
{
 $db->postTesting($data, $table);
}
else
{
 echo "Please fill in everything!";
}

<?php


class Database
{

    private $connection;
    private $typedb = "mysql";

    private $host = "127.0.0.1";
    private $dbname = "oopphp";
    private $username = "root";
    private $password = "";

    public function __construct()
    {

    try{
        $this->connection = new PDO($this->typedb.
                           ":host=".$this->host.
                         ";dbname=".$this->dbname,
                                    $this->username,
                                    $this->password);

        $this->connection->setAttribute(PDO::ATTR_ERRMODE,
                                        PDO::ERRMODE_EXCEPTION);

        return $this->connection;
        }

    catch(PDOException $e)
      {
        throw new Exception("Connection failed: ".$e->getMessage());
      }

    }

    public function postTesting($data, $table)
    {
        try{
        //var_dump($table, $data);
        $columns = "";  
        $holders = "";

         
         foreach ($data as $column => $value)
         {  
             //var_dump($column);
             //var_dump($value);
            $columns .= ($columns == "") ? "" : ", ";  
            $columns .= $column;  
            $holders .= ($holders == "") ? "" : ", ";  
            $holders .= ":$column";

            //var_dump($columns);
            //var_dump($holders);
        }  


         $sql = "INSERT INTO $table ($columns) VALUES ($holders)";  
         //return $sql;

         $stmt = $this->connection->prepare($sql);
         //var_dump($stmt);
        

        
         foreach ($data as $placeholder => $value)
         {
         $stmt->bindValue(":$placeholder", $value);        
         //var_dump($stmt);
         //var_dump($placeholder);
         //var_dump($value);
          }
        
         //var_dump($sql);
         //var_dump($stmt);
          $stmt->execute();
      }

    catch(PDOException $rError)
      {
        throw new Exception("Registering Failed: ".$rError->getMessage());
      }
   }
}

         foreach ($data as $column => $value)
         {  
            //var_dump($column);
            //var_dump($value);

            $columns .= ($columns == "") ? "" : ", ";  
            $columns .= $column;  
            $holders .= ($holders == "") ? "" : ", ";  
            $holders .= ":$column";

            //var_dump($columns);
            //var_dump($holders);
        }